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M42 and M43 24-25/10/14


Johnnyaardvark
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M42 - composite for HDR.

8x 3minutes outer ISO800.
23x 20seconds and 29x 8 second exposures for the core at ISO800.

Trapezium 29x 8 second at ISO800

 

All with a stack load of darks and about 18 flats.

 

ED80, HEQ5 Pro and Nikon D5000 unguided.

 

Stacked in DSS and processed in CS2.

 

Feedback and comments welcome :)

 

Thanks

 

Steve

 

15458659580_e8d4ae9073_h.jpgM42 EMS3 by sja88, on Flickr
 

Edited by Johnnyaardvark
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Thanks all for the encouragement. :-)

Stephen. Bet the image looks a little different to the raw test images you saw on the Friday night although amazingly the colour was there.

Quite bizarre how it loses that after stacking and it then needs pulling out again in the processing.

Still really happy with how it turned out. S

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Guest Phillyo

Very nice M42 here, perhaps the blacks are a little clipped? You might be able to tease out a little more nebulosity if you take the black back up a little bit?


 


Great effort.


 


Phil


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Guest Phillyo

I'm guessing you used photoshop or a similar program? If so then it's your levels. If you've already saved it then you may need to go back to the autosaved tiff file from DSS and start again. Adjust the curves first (Ctrl+M) to bring the detail of the nebula out then adjust the levels (Ctrl+L) to bring the black point up. Don't take the black point past the start of the histogram curve as that's when you'll start clipping the black data.


 


Hope that makes sense, if not let me know :)


 


Phil


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Curves first then levels? Interesting, like most folk I do it the other way round! But ]next image I work on I'll try curves first! :)


 


Cheers


Ron


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Guest Phillyo

I use Pixinsight now so forget which way to do it, but I thought it was curves then levels first. Don't suppose it matters as long as you don't clip the black point. Leave the background at around 50-60 until your final edit then drop it to about 30. Shouldn't be much darker than that I think? (been a while).


 


Phil


 


Edit: Yours are around 10ish which is too low :)


Edited by Phillyo
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Actually have not changed the levels themselves much as I thought that changing the curves alone was a different way of editing the same thing? I don't fully know as I mostly only "play" with this software so am far from an expert... more a "tweak and see user" and play it by ear [read eye!] :)


 


Where would I find reference to these numbers/levels "background at 50-60" and my current values of about 10? Had a little play... is it the middle of the highest peak on the histogram? And if so what determines if I am looking at the levels of the "background?"


 


Thanks for the input as it's all useful and much appreciated.


 


Regards


 


Steve


Edited by Johnnyaardvark
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Guest Phillyo

Hi Steve.

Levels and curves do two different things so really you 'should' adjust the curves quite harsh on the first stretch followed by moving the black point up towards the left edge. Then repeat with a slightly less harsh iteration of curves, then move levels again etc. Don't go too far though. You'll know when it's about far enough by either practise, looking at the image or more accurately looking at the histogram.

When the histogram no longer has one nice high peak and is more stretched out then you've gone as far as you can go really. Then you can remove gradients, noise, star shrink, add some contrast and sharpen the image a small amount...all to taste :-)

If you want to see what level your background is at then if you right click on the dropper tool on the left hand side of photoshop you'll get another option (can't think of its name right now as I'm using my tablet to type this from my bed!) Place 4 of them around your image and on the right hand side above layers pane and above the history/actions panes you'll see the numbers in rgb value, that denotes the red, green and blue values for your image. Ideally they want to be about the same for the background (try to avoid clicking on any nebulosity) and should be approx 30. You can drop it a little lower if you like, again to taste, but 20 should be the absolute lowest value.

Hope that makes sense, if not let me know and I'll try to add some screen shots to explain better the next time I'm on the PC.

Cheers,

Phil.

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Plenty of detail in there Steve, nice image.

I gave up on DSS after fighting to get the colour back with my modded 1000d images. It just seemed to desaturate the images beyond rescue

In photoshop, levels, curves nor saturation couldnt pull the colour out. I went through loads of options and couldnt get it right. I then invested in Images + and the very first process using the align, stack routine brought all the colour out.

Not used Dss since

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Thanks Stephen, Phil and Rob...


 


I like the free route but will have a look at that software you suggested Rob.


 


Thanks for the info Phil. Think I have found all the bits last night... good info. Some of which I do already. Saturation increase required for colour (as per Robs comment/problems with DSS). At what point would you increase saturation?


 


Gradient removal... hoped to avoid that by adding flats. These are the first where I have attempted that but some of my flats were not perfect but has produced some of my best/flattest images to date so was quite happy with that.


 


Had a play with some suggested techniques for reducing star bloat. Interesting but not quite as good as I would like I guess.


 


Struggled a little keeping the background higher than 10 after adjusting curves/levels partly as a starting point the background mostly shows about 30 (or so) max only for the RGB values of the stacked raw output from DSS.


 


Anyhow... had a play and made sense of your advice. Nothing to show for it yet though as needs a little more subtlety in the adjustments than I gave it last night! More time required and I am back at work so will have more of a go when I can make time :(


 


Thanks again for the comments/advice and suggestions. Really appreciated!


 


Steve


Edited by Johnnyaardvark
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